The B53 bomb, built at a now-shuttered weapons plant in Burlington, Iowa, was carried by aircraft and remains one of the highest-yield nuclear weapons ever fielded by U.S. forces.

The bomb, which first was introduced into the U.S. stockpile in 1962, posed a major dismantlement challenge for weapons experts, in part because of its size and weight - more than 10,000 pounds.

Pantex, about 17 miles northeast of Amarillo, retrofits older warheads with newer equipment and dismantles atomic weapons retired from duty. The plant also stores tons of plutonium from retired warheads in a series of underground bunkers.

Several years ago, the National Nuclear Security Administration created a new process, dubbed SS-21, aimed at increasing safety by incorporating new technology, tooling and intensive personnel training into the dismantlement process. New tooling and processes, once fully operational, will help Pantex workers safely dismantle B53s.

"The tooling and processes developed for the B53 dismantlement program is part of NNSA's commitment to employing the best science and technology in the world to solve complex national security challenges," said Brig. Gen. Garrett Harencak, a top NNSA official who recently visited Pantex to see the proposed B53 dismantlement process.

"Whether we're securing vulnerable nuclear material around the world, ensuring the safety and reliability of our stockpile or safely dismantling weapons that are no longer needed, our dedicated engineers and researchers work every day to improve the efficiency and effectiveness of our mission."

Teams from contractor B&W Pantex, the NNSA, Sandia National Laboratories and Los Alamos National Laboratory helped develop the new process.

"We collaborated closely with the design agencies," said Steve Young, Engineering Division manager at B&W Pantex. "A set of tooling was fabricated and delivered to Sandia joined by a team from Pantex. We worked side by side to ensure the process performed as designed."

The project team is expected to receive the go-ahead to begin disassembling B53s after extensive safety reviews, safety analyses and nuclear explosive safety studies.

Pantex is expected to play a major role in weapons dismantlement for years to come as older weapons are retired from the nation's nuclear arsenal.

Top administration officials revealed this week that the U.S. stockpile includes more than 5,100 nuclear weapons - 5,113 as of Sept. 30 - and about 4,500 warheads waiting to be dismantled.